1. Field
The field relates to an organic electroluminescence display and a driving method thereof preventing flashover at an initial driving thereof.
2. Description of the Related Technology
With developments in technology relating to thin film transistors and semiconductors, active matrix type flat-panel displays using a thin film transistor have been widely used. In particular, an organic electroluminescence display, has excellent properties of luminous efficiency, brightness, viewing angle, and rapid response speed.
The organic electroluminescence display displays images by using a plurality of organic light emitting diodes (OLED). The respective organic light emitting diodes include an anode electrode, a cathode electrode and an organic light emitting layer positioned therebetween and light is emitted by means of the recombination of electrons and holes.
FIG. 1 is a graph showing voltage levels according to time sequence of power generally supplied to an organic electroluminescence display. Referring to FIG. 1, the organic electroluminescence display is driven by receiving a pixel power supply ELVDD and a ground power supply ELVSS having voltage lower than the pixel power supply ELVDD.
The pixel power supply ELVDD is generated by boosting a voltage so that the ELVDD voltage levels are gradually raised, as shown in FIG. 1. And, the ground power supply ELVSS may be gradually lowered.
The organic electroluminescence display operates in response to the pixel power supply ELVDD and the ground power supply ELVSS. However, at start up the difference of the voltage levels of the pixel power supply ELVDD and the ground power supply ELVSS increases over time. As a result, the highest pixel power supply ELVDD and the lowest ground power supply ELVSS are provided to the pixels in the last horizontal line of the organic electroluminescence display.
Therefore, the lower portion of the organic electroluminescence has a relatively high brightness, which is perceived as glare.